Field
This invention relates to semiconductor device fabrication and, more particularly, to processes using etch stop layers.
Description of the Related Art
Semiconductor device fabrication processes, e.g., for making integrated circuits, may involve various pattern transfer steps in which an etch process is used to transfer a pattern in a masking layer into an underlying target layer. To prevent undesired etching or damage to material that underlies the target layer, an etch stop may be provided between the target layer and the underlying material to be protected. As the features of semiconductor devices have become ever smaller, the requirements for the etch stops have become more stringent. Accordingly, there is a continuing need to develop etch stops compatible with the fabrication of modern semiconductor devices.